Experimental Investigation of an Optical Reservoir Computing System Based on Two Parallel Time-Delay Reservoirs

Dian-Zuo Yue,Guang-Qiong Xia,Chun-Xia Hu,Yu-Shuang Hou,Zheng-Mao Wu,Zhen-Zhen Xiao

doi:10.1109/jphot.2021.3075055

Dian-Zuo Yue, Guang-Qiong Xia + Show 4 more

Open Access

https://doi.org/10.1109/jphot.2021.3075055

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Abstract

We experimentally investigate the performances of an optical reservoir computing (RC) system based on two parallel time-delay reservoirs composed of two semiconductor lasers (SLs) subject to optical feedback. In such a system, the information being processed is split into two parts to send into two reservoirs through directly modulating the pump currents of two SLs, and the temporal output of the two SLs are sampled and taken as the virtual node states for training and testing. Via Santa Fe time series prediction task and multi-waveform recognition task, the performances of the proposed RC system are investigated and compared with those of the system based on one reservoir. The results show that the system based on two parallel reservoirs behaves better performance and stronger parameter robustness than that based on one reservoir. Moreover, through analyzing the dependence of the system performances on the number of virtual node states actually used for readout, the potential data processing rate (DPR) of the system is evaluated. For processing a prediction task under guaranteeing the normalized mean square error below 0.1 and a recognition task under guaranteeing the signal error rate below 0.005, the potential DPR of the proposed RC system can achieve 200 MSa/s, which is twice the DPR of the system with only one reservoir.

Highlights

Nowadays, with the advent of big data era, the demand for efficient information processing technique is growing rapidly
We experimentally investigate the performances of an optical reservoir computing (RC) system based on two parallel time-delay reservoirs composed of two semiconductor lasers (SLs) subject to optical feedback
We experimentally investigate the performance of an optical RC system based on two parallel time-delay reservoirs which are constituted of two distributed feedback SLs (SL1, SL2) subject to optical feedback, respectively

Summary

Introduction

With the advent of big data era, the demand for efficient information processing technique is growing rapidly. Among ANNs, recurrent neural network (RNN) is capable of performing time-dependent tasks, but it is time-consuming to train the network weights of the input layer, the hidden layer, and the output layer. The reservoir is composed of a large number of nonlinear nodes, and such an RC is usually named as spatially distributed RC [6]. It has been demonstrated that the reservoir in RC can be composed of a single nonlinear node with a time-delay feedback loop, and the corresponding RC is named as time-delay RC (TDRC) [7]. Speaking, TDRC is easier to implement than spatially distributed RC, since its reservoir consists of only a single nonlinear node and a feedback loop. Several groups have implemented TDRCs based on different time-delay systems including electronics [7], [8], optoelectronics [9]–[13], and optics [14]–[17]

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Results

Conclusion